/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.io;

import java.io.*;

/** A WritableComparable for longs. */
public class LongWritable implements WritableComparable {
	private long value;

	public LongWritable() {
	}

	public LongWritable(long value) {
		set(value);
	}

	/** Set the value of this LongWritable. */
	public void set(long value) {
		this.value = value;
	}

	/** Return the value of this LongWritable. */
	public long get() {
		return value;
	}

	public void readFields(DataInput in) throws IOException {
		value = in.readLong();
	}

	public void write(DataOutput out) throws IOException {
		out.writeLong(value);
	}

	/** Returns true iff <code>o</code> is a LongWritable with the same value. */
	public boolean equals(Object o) {
		if (!(o instanceof LongWritable))
			return false;
		LongWritable other = (LongWritable) o;
		return this.value == other.value;
	}

	public int hashCode() {
		return (int) value;
	}

	/** Compares two LongWritables. */
	public int compareTo(Object o) {
		long thisValue = this.value;
		long thatValue = ((LongWritable) o).value;
		return (thisValue < thatValue ? -1 : (thisValue == thatValue ? 0 : 1));
	}

	public String toString() {
		return Long.toString(value);
	}

	/** A Comparator optimized for LongWritable. */
	public static class Comparator extends WritableComparator {
		public Comparator() {
			super(LongWritable.class);
		}

		public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
			long thisValue = readLong(b1, s1);
			long thatValue = readLong(b2, s2);
			return (thisValue < thatValue ? -1 : (thisValue == thatValue ? 0
					: 1));
		}
	}

	/** A decreasing Comparator optimized for LongWritable. */
	public static class DecreasingComparator extends Comparator {
		public int compare(WritableComparable a, WritableComparable b) {
			return -super.compare(a, b);
		}

		public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
			return -super.compare(b1, s1, l1, b2, s2, l2);
		}
	}

	static { // register default comparator
		WritableComparator.define(LongWritable.class, new Comparator());
	}

}
